Biochar for a sustainable EAF steel production
The previous GREENEAF project (RFSR-CT-2009-00004) has demonstrated the feasibility of utilization of char, from biomass, as substitute of coal into the EAF. The present project objective was to make the char use a standard practice.
Therefore, the following activities have been carried out:
- char laboratory characterizations to check the capability of the material to replace coal in industrial trials, both for charging and injection procedures,
- identification of most suitable injections systems
- analysis of EAF behaviour in case of char and biomass use during long-time industrial trials
- Life Cycle Assessment study, as regard to inventory issues.
Industrial trials of EAF charging confirmed the feasibility of coal substitution and outlined the relevant process aspects: basket preparation to avoid material burning before dissolution into molten steel and EAF post combustion to recovery the energy content of the char volatile matter.
In case of injection trials, a wide range of possibilities has been exploited: biochar, biochar mixed with fossil coal and virgin ligneous biomass. The best slag foaming, comparable with the pulverised fossil coal injection has been obtained with virgin biomass.
Outlined energy saving with EAF equipped for post combustion and tailored char production form low grade biomass showed that char utilization is economically sustainable.
This research received funding from the European Community’s Research Fund for Coal and Steel (RFCS) under grant agreement n° RFSP-CT-2014-00003.